Ingot mold



' Sept. 12, 1944. LINDEMUTH 2,353,171 meow MOLD I Original Filed Dec. 1-1, 1941 2 ShQet' s-Sheet 1 fl n l T IT v Q r INVENTOR.

BY WM A 'IORNEYS p B. LINDEMUTH} 3 Original Filed Dec. 11, 1941 2 Sheets-Sheet 2 E rm o 0 v fi Patented Sept. 12, 1944 UNITED STATES PATENT OFFICE Original application December 11, 1941, Serial No.

Divided and this 1943, Serial No. 489,365

3 Claims. (CL 22-469) .1941, which issued on July 20, 1943 as Patent #2,324,786 reference to which is hereby made.

Ingot molds having a corrugated or fluted interior are preferred for casting large ingots, be-

application June 2,

by gradually tapering the outer vertices of the mold corrugations or fiutings, inwardly to the diameter of the inner Vertices thereof at a point somewhat above the lower edge of the mold, and by imparting a circular section to the mold between this point and the lower edge. The raised portion of the stool may now likewise be made of circular section and of such diameter as to fit loosely within the circular base of the mold, so that the mold may be easily placed in position over the raised portion of the stool. To further cause they minimize the tendency of the ingot to crack on cooling and solidifying. If, for'example, the mold were of circular section, the ratio of the perimeter to cross-sectional area of the ingot would be a minimum, so that there is no excess surface metal to draw upon as the outer portion of the ingot tends to'cool and contract uniformly against its still molten interior. Cracks and fissurestherefore develop. With the corrugated or fluted mold, on the other hand, the perimeter is greatly increased in relation to the cross-sectional area, so that as the ingot metal cools, it may contract initially at the outer vertices of the corrugations or fiutings, and in this way eliminate any tendency to crack.

The, molds employed for casting large ingots are usually open at both ends, and the casting efiected bystanding the mold on a cast iron base or stool.- If, however, any of the molten metal seeps between the base of the mold and the stool, it forms a fin on solidifying, which prevents the ingot from being lifted out of the mold without injury. In accordance wtih a feature of my invention, I overcome this 'defect by providing the stool with a raised or elevated portion adapted to fit loosely within the base of the mold, and by filling in the intervening space or crevice with some powdered material which does not contaminate the ingot metal, such as ferro-silicon, ferro-chrome, ferro-manganese, etc., in the casting of steel ingots. However, in the case of a corrugated or longitudinally fluted ingot, it .is dlfiicult ande pensive to form thisraised portion of the steel with corresponding corrugations or fiutings in such manner as to eliminate-binding. becauseboth the mold and the stoolarev formed by casting, so that slight. irre ularities in the corrugations, etc., inevitably occur. Also; it is difilcult in placing the moldon the'stool to prop mold proper with those in the stool.

;I,ov e rcome this difllculty by making the moldof facilitate this, I impart slight, opposite, conical tapers to the circular base of the mold and the raised portion of the stool, themold being tapered downwardly and inwardly, and the stool upwardly and inwardly. The taper onthe elevated por-' tion of the stool is made sufiiciently great, as explained below, that as the ingot shrinks, it can not bind or tear. The circular tapered portions at the base of the mold and in the elevated por-- tion of the stool need not be machined. Sufficient clearance can be provided so that ordinary casting suffices, owing to the tolerance available. As before, the crevice occurringv between these tapered circular portions of the mold and stool is filled in with some powdered material which does not contaminate the ingot, such as ferro-silicon,

' etc., in the casting of steel ingots. With this construction and arrangement of the mold and stool, no fins of ingot metal can form and solidify therebetween to bind the ingot to the mold. Accordingly, the ingot may be easily removed from the mold when sufliciently solidified.

Various further and more specific objects, features and advantages will appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate merely by way of example, a preferred form of the invention. The invention consists in such novel features, arrangements and combinations of parts as may be shown and described in conneclindrical type, but various ,featuresofinvention 7 maybe used in connection with other typesof molds with either thelarge, or the small and uppermost and of various cross-sectional shapes suchassquare, octagonal, etc.

- n.the drawings-F. a

Fig. 1 is :avertical sectional viewgofsan ingot mold and accompanying parts embodying the invention,'the,1mold,being ;shown asfilled with c lar sectionat its base, which is accomplished molten metal: 1

' Fig. 2 is a view similar to Fig. 1, but with the parts in the position which they will assume upon cooling and contraction of the ingot;

Fig. 3 is a vertical sectional view of the upstanding tubular portion of a corrugated type ingot mold embodying features of the invention;

Figs. 4 and 5 are sectional views taken respectively along lines 4-} and 5--5 of Figs. 1 and 2;

Fig. 6 is a bottom view of the mold portion of Fig. 3; and

Fig. '7 is an enlarged sectional view of a portion shown at the bottom of Fig. 2.

Referring to the drawings in further detail, a tubular upstanding portion l0 of the mold is made, for example, of cast iron, and has interior walls formed with corrugations as at ll.

(The term "corrugations herein is intended to include flutes of various types.) Except at the top and bottom portions of the molds, the corrugations may be of suitable well-known dimensionsand shapes. At the top, the wall area is formed into a smooth annulus, as at l2, this portion of the mold .cavity preferably being of a diameter about equal to the diameter of the adjacent corrugated areas as measured at the deepest parts or outer vertices of the corrugations. Also this area is preferably finished to accurate dimensions as by machining. Starting at. a region substantially below the lower edge of the area H, the corrugations as shown are gradually reduced in size toward the top, as by a gradual taper l3 upwardly and outwardly of the mold,.

until they merge smoothly into the annular area. A sheet metal sinkhead I4 is adapted to have its lower portion inserted to a predetermined depth as shown, within the upper end of the mold. Such sinkheads may be made by bending relatively thin sheet metal into a tubular shape and finishing same for accurately corresponding as to shape, to the smoothly finished f area I2. For a relatively large ingot mold, 18- gauge sheet steel for example, will be satisfactory for such sinkheads. The sinkheads are preferably made of a size to normally provide, when the parts are cool, a predetermined clearance space between the non-corrugated mold wall area and the external surface of the inserted portion of the sinkhead. This clearance space should be rather accurately determined so that when the sinkhead first reaches about its maximum temwill at no time expand enough to more than slightly bind temporarily within the top of the mold. Thus not only will danger of buckling be avoided, but at the time when the mold is at first filled with molten metal, the clearance space will either beat a minimum or'disappear entirely. Ordinarily a clearance of about inch I 'all around, when the parts are at room temperatures, will be sufficient for this purpose. But it will be appreciated that accurate determination of the proper clearance will depend upon the dimensions or the sinkhead and mold parts, as well as the temperature or themetal being poured into the mold.

The portion of the sinkhead protruding from the mold may be surrounded'by a box-like structure including for example a cylindrical sheet 'metal wall ll formed with an inturued bottom flange l6 resting on the top of the mold. This structure provides a receptacle surrounding the spaced substantially from the sinkhead and the intervening space will be filled with a suitable packing 20 formed for example of clay or asbestos rope.

When the parts are initially put in place, they will assume the position shown in Fig. 1, with the packing 20 retaining the sinkhead at the proper elevation. Thereupon when the molten metal is poured into the mold, the sinkhead will quickly expand in diameter before the mold expands substantially. Then the mold will ultimately expand in height and radially. Subsequently as the external shell of the sinkhead portion of the ingot solidifies, it will fuse or weld to the sinkhead and cause contraction. of the latter. Meanwhile and subsequently, as the ingot becomes cooler, it will contract in height as well as in cross section. That is, at least the more protruding portions of the corrugated side walls of the ingot will become spaced from the more deeply recessed portions of. the corrugations on the mold walls, and also the upper portion of the ingot and the sinkhead welded thereon will have slid down with respect to the upper end of the mold to positions as shown.

If the upper ends of the corrugations I3 terminated abruptly, it will be apparent that opportunity would be afiordedfor a fin to form on the ingot extending out over the tops of the corrugations at the lower edge of the sinkhead. Andin that event the ingot could not shrink down without fracture, etc. However, with the gradually tapered upper end portions [3 of the corrugations, the ingot is free to contract vertically and to its width. If the angle of the taper is less than this amount, then there will be danger when the ingot shrinks in height, that the lower edge of the sin khead may at some points jam against the tapered portions of the corrugations. For example, if the mold is five times as high as its width, then the slope should have a maximum ratio of about 5:1. In that case, a slope ratio of 4:1 would not be sufilcient, although a smaller ratio of, say, 6:1 woud be satisfactory.

After the ingot is solidified, it may be removed from the mold by grasping the projecting portion of the sinkhead with lifting dogs or tongs.

The molding portion [0 is adapted to rest upon a cast iron stool as at 22. As shown, this stool is formed with a flat annular peripheral area 23 upon which the lower edges of the portion III are adapted to rest. Inside this peripheral area, the stool may be formed with a raised area 24 which preferably joins the peripheral area by a tapered annular area 25 inclined upwardly and inwardly from the vertical by about l5- for example. Within the lower end of the portion III, the deepest portions of the corrugations are preferably tapered downwardly and inwardly of the mold until they merge to form an annular non -oorrugated surface as at 26 around within the bottom edge of the mold, i. e., a surface from which the corrugations have disappeared. The diameter of this non-corrugated annular surface is preferably about the same as the minimum diameter of the mold cavity as measured at the inner vertices of the mold corrugations, and the annular portion is slightly tapered downwardly and inwardly, as will be apparent in Fig. 6. Also this diameter is preferably such as to provide a substantial clearance space 21, of for example about A inch, around the raised area 24 on the stool, in order to enable the mold to be easily placed on the stool.

This clearance space 21 is adapted to be filled with a suitable luting material which will ,not contaminate the molten metal. For example, in the casting of steel ingots, powdered ferro-silicon or the like may be used for this purpose, since it will not injure the steel if some of it should get into the molten metal in view of the fact that all steel contains a certain amount of silicon. Finely divided ferro-manganese; ferro-chrome, etc., may also be used, as well as other materials, provided the ingredients thereof are selected from among the materials present in the molten metal for which the mold is intended to be used.

The constructional features as above described at the bottom of the mold are such as to prevent 'any danger of formation of a radially-extending fin between the stool and the body portion of the mold. Any such fin would of course prevent the ingot from being removed upwardly from the mold without breakage. The corrugatedwall sur-' While the invention has been described in detail with respect to particular preferred examples, it will be understood by those skilled in the art after understanding the invention, that various changes and further modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and modifications. I

What is claimed as new and desired to be secured by letters Patent is:

1. An ingot mold comprising a tubular upstanding portion, a stool'portion having peripheral areas upon which the bottom edges of the tubular portion are adapted to rest in continua stool portion, the interior walls of said body,

portion being generally cylindrical but formed with numerous longitudinally extending corrugations, the lower interior wall surface areas between corrugationsbeing tapered in a downward and inward direction until they merge into a smooth wall area extending around within the faces within the lower end of the mold as tapered downwardly and inwardly (as contrasted with an opposite form of taper at theupper end) make it possible for the lower end of the mold cavity to be non-corrugated while enabling the ingot to be removed upwardly. This non-corrugated area enables the mold to be lowered into proper position on the stool without danger, of jamming or breaking any protruding portionsof corrugations, and also makes it possible to more easily apply the luting material without danger of leaving irregular gaps which would aflord space for fins or protruding portions on the ingot. The inclined position of the surface 25 on the stool insures of the type having its smaller end uppermost. then the corrugations shouldbe-tapered downwardly and outwardly at the bottom, and the wall surfaces between corrugations shouldbe tapered upwardly and inwardly at the top. 1. e., the'construction would then be substantially that of Fig. 3 as viewed upside down.

into the clearbottom of the mold cavity, said smooth wall area defining a' bottom opening for the body portion, of a cross section such that approximately straight line downward continuations of the inner vertices of the corrugations form elements of said smooth wall area, said stool portion having peripheral areas upon which the bottom edges ceiving sealing material.

ward direction until they-merge into a smooth wall area extending around within the bottom of the mold cavity, said smooth wall area defining,

a bottom opening of a cross section such that approximately straight line downward continuations of the inner vrtices of the corrugations form elements of said smooth wall area.

' LEWIS BYRON LINDEMUTH. 

